Truck door lock



May 26, 1970 v. 0. SMITH mnucx noon LOCK Filed Sept. 21, 1967 3 Sheets-Sheet 1 I I I INVENTOR.

VEE/VO/V 0. 6/7/77) y 1970 v. 0. SMITH 3,514,142

TRUCK DOOR LOCK Filed Sept. 21, 1967 3 SheetS-Sheet .3

, INVENTOR.

2 z //V0/V 0. (SW/779 ZMMMQWMW v. 0. SMITH 1 3,514,142

TRUCK DOOR LOCK May 26, 1970 3 Sheets-Sheet 5 Filed Sept. 21, 1967 INViJTOR United States Patent 3,514,142 TRUCK DOOR LOCK Vernon 0. Smith, Ashley, Ohio, assignor to Overhead Door Corporation, Marion, Ohio, a corporation of Indiana Filed Sept. 21, 1967, Ser. No. 669,481 Int. Cl. Eb /02; E05c 19/72 U.S. lCi. 292-113 9 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION This invention relates in general to a lock structure for an upwardly-acting truck door and, more specifically, to a type thereof which is capable of adjusting automatically to avoid looseness in the door incident to Wear or the tolerances of conventional installation, and which is incapable of accidental opening.

Persons familiar with the manufacture and maintenance of upwardly-acting doors for truck vans, for example, have long been aware that the lock structures for such doors are subject to unusually rough treatment from the substantially normal conditions of use to which they must be exposed. That is, they are constantly exposed to the weather, they are often battered, or exposed to strains by, the loads carried by the truck, and they are frequently subjected to excessive and destructive forces when the truck or other vehicle upon which they are mounted moves over uneven terrain. As a result, any looseness in the connections of the latching mechanism, which can be produced by normal wear, by improper initial adjustment or by a slightly defective part, will quickly produce excessive and abnormal wear or even complete failure. Where this looseness involves the connection between the latch bolt and its catch, the result is a dancing door which obviously aggravates the problem and accelerates failure. That is, because the loose connection does not firmly hold the door in its closed position, the door will tend to vibrate in a variety of directions as the vehicle thereof moves along substantially any terrain.

By reference to the structure disclosed in Pat. No. 3,108,833, it will be seen that existing latch bolts are usually provided with some type of lengthwise adjustment to remove looseness between the hook portion of the latch bolt mounted on the door and the normally rigid catch attached to the truck. Frequently this adjustment is effected by means of a threaded connection between the shank of the latch bolt and the hooked portion at the lower end thereof. This construction adds materially to the cost of the lock construction and, more importantly, creates additional problems. For example, if the hooked portion is accidentally moved during operation, it may be out of alignment with the catch and either fail to make a secure connection or damage the catch box, due to its improper positioning.

In addition to the foregoing problems of wear, accelerated failure and maladjustment of the lock structure, there is the further problem that a worn lock mechanism ice may open of its own accord and thereby permit the door to raise and expose, or even accidentally discharge, the load from the truck as it is moving along a road.

Accordingly, a primary object of this invention is the provision of an improved lock structure for an upwardly acting truck door wherein the lock structure is automatically adjusted to avoid looseness resulting from normal wear, minor errors in installation and acceptable tolerances in parts, whereby the useful life of the lock structure and/ or the door would be severely reduced.

A further object of this invention is the provision of a lock structure, as aforesaid, in which the one-piece latch bolt is mounted so that it can be removed from its latched position only by overcoming a resiliently flexible force urging it into the locked position and wherein the actuating arm of the lock mechanism is engageable by a gravity operated keeper, which can also serve as a sealing device and which can be moved into a completely inoperative position when desired.

A further object of this invention is the provision of a lock structure, as aforesaid, which requires no adjustment when installed and which cannot be disengaged by the shocks created when the truck upon which the lock structure is mounted is moved over unusually rough terrain.

A further object of this invention is the provision of a lock structure, as aforesaid, which can be installed in a manner corresponding to existing lock structures by any person capable of installing such existing lock structures and which can be easily operated by any person capable of operating the truck.

Other objects and purposes of the invention will become apparent to persons who understand lock structures upon reading the following descriptive material and examining the accompanying drawings, in which:

FIG. 1 is a side elevational view of the lock structure embodying the invention as appearing on a fragment of a truck door structure.

FIG. 2 is a sectional view taken along the line IIII in FIG. 1.

FIG. 3 is a sectional view taken along the line IIIIII in FIG. .2.

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3.

FIG. 5 is a fragment of FIG. 3 showing part of the structure thereof in a different position of operation.

FIG. 6 is a fragment of FIG. 3 showing the structure of FIG. 5 in another position of operation.

FIG. 7 is a fragment of FIG. 1 showing part of the structure thereof in a different position of operation.

FIG. 8 is a sectional view taken along the line VIII-VIII in FIG. 4.

FIG. 9 is a fragment of FIG. 1 showing part of the structure thereof in a different position of operation.

FIG. 10 is a fragment of FIG. 1 showing the structure of FIG. 9 in another position of operation.

FIG. 11 is a fragment of FIG. 1 showing the structure of FIG. 9 in a further position of operation.

FIG. 12 is a sectional view taken along the line XII-XII in FIG. 1.

FIG. 13 is a sectional view taken along the line XIIIXIII in FIG. 1.

For convenience in description, the terms upper, lower, left, right, front, rear and words of similar import will have reference to the lock structure of the invention and the parts of the truck door construction associated therewith as appearing in FIG. 1 which discloses the rear side of the lock structure. The terms inner, outer and derivatives thereof will have reference to the lock structure of the invention and parts associated therewith.

3 SUMMARY OF THE INVENTION The objects and purposes of the invention, including those set forth above have been met by providing a lock structure comprising a catch box mounted in the bed of a truck or similar vehicle, and a latch mechanism mounted upon an upwardly acting door of the truck van and having a latch bolt engageable with a resiliently biased catch in the catch box. The latch bolt is pivotally mounted upon an actuating member having an arm which is engaged by a primary keeper and a secondary keeper, said secondary keeper being movable into an inoperative position during periods when the lock mechanism is being operated frequently. The latch bolt is mounted on the actuating member so that the spring bias of the catch tends to oppose the initial unlocking movement of the actuating member.

DETAILED DESCRIPTION The lock structure of the invention, a preferred embodiment of which is disclosed in FIGS. 1 and 2, is comprised of a latch assembly 11, which is mounted upon the lower end of an upwardly acting door 12 for engagement with a catch assembly 13 which is mounted in the bed 14 of an otherwise substantially conventional truck van, of which the door 12 is a part. In this particular embodiment, the door 12 is comprised of a plurality of horizontally hinged sections which are disposed in a substantially vertical plane when the door is closed and in a substantially horizontal plane near the room of the van when the door is open. A resiliently flexible weather seal 15 (FIG. 4) is mounted upon the lower edge of the door 12 and is engageable with the bed 1 4 in a conventional manner and for conventional purposes. A truck door of this general type is disclosed in US. Pat. No. 3,227,205, which is assigned to the assignee of this application.

The catch assembly 13 (FIGS. 1, 3 and 4) is comprised of an elongated, substantially rectangular casing 16 which is preferably fabricated from sheet steel to form a bottom wall 17, a top plate 1 8, a pair of end walls 21 and 22 (FIG. 3) and a pair of sidewalls 23 and 24 (FIG. 4). The bottom wall 17 has an elongated, narrow slot 26 through which moisture and the like can drain. The sidewalls 23 and 24 have openings 27 and 28, respectively, through which dirt and other foreign material can escape from the chamber 29 within said casing 16. The top plate 18 preferably extends beyond the end walls 21 and 22 and the sidewall 23 for engagement with the upper surface 32 (FIG. 1) of the bed 14 when the casing 16 is located within the opening 33 in the bed 14. The top plate 18 has an opening 34 through which the latch bolt 36 is loosely and swingably received, as shown in FIGS. 3 and 6.

The catch assembly 13 includes a catch lever 37 which is pivotally supported at its rightward end (FIG. 3) upon a pivot pin 38 which is secured to and extends between the sidewalls 23 and 24 of the casing 16. The catch lever 37 has near its leftward end an integral hook 39 which projects upwardly and then curves rightwardly and downwardly for engagement with a cooperating hook 42 on the latch bolt 36. The opening 34 is located in the top plate 18 so that a substantial portion of the hook 39 is covered by the top plate 18. Accordingly, the pivotal movement of the catch lever 37 is positively limited by and between the top plate 18 and the bottom wall 17.

A spiral spring 43 (FIG. 3) is disposed between and constantly held under compression between the top plate 18 and. the leftward end portion 44 of the catch lever 37. Guide pins 46 and 47 are mounted upon and project toward each other from the top plate 18 and the left end 44 of lever 37 for reception into the opposite ends 'of the spiral spring 43 whereby accidental lateral displacement thereof is prevented.

In this embodiment, the spring 43 exerts a downward force against the catch lever 37 of approximately 100 pounds, near the point of engagement between the hooks 39 and 42, when the lever 37 is hearing against the bottom wall 17. Movement of the hook 39 into engagement with the undersurface of the top plate 18, against the contrary urging of the spring 43, requires a force, exerted near the point of the connection of the hooks 39 and 42, of approximately 500 pounds. This arrangement of forces is designed for an average upwardly acting truck door and, therefore, can be varied as desired to meet the specific requirements of the type and weight of the door involved. In fact, a wide range of variations in these forces can be achieved merely by using a different spiral spring 43.

It has been found that a lever 37 (FIG. 3) capable of approximately one-half inch of movement in the region of the hook 37 is adequate for overcoming maladjustments of installation and distortion of the associated door and lock parts resulting from the usual wear and rough treatment to which the door and the associated truck structure are exposed.

The top plate 18 (FIG. 1) may be secured to the bed 14 by welding, by screws or any other convenient, conventional means.

The latch assembly 11 (FIG. 1) has a mounting plate 51 which is secured to the outer surface of the door 12 adjacent the lower edge thereof by means of bolts or rivets 52. A latch support member 53 is comprised of a substantially oval-shaped housing 54 having front and rear sidewalls 56 and 57, respectively, which are interconnected by a peripheral wall 58 having a substantial opening 59 (FIG. 3) along a substantial portion of the housing 54. The latch support member 53 is rotatably supported upon the mounting plate 51 by an axle 62 which is rigidly secured to the mounting plate 51 and is rotatably received through appropriate openings in the sidewalls 56 and 57 of the housing 54.

The latch support member 53 (FIG. 1) has an integral arm or handle 63 which projects from the housing 54 in a direction substantially radially of the axle 62 and on the opposite side thereof from the opening 59 in the peripheral wall 58. The arm 63 includes an integral, frontwardly extending and substantially U-shaped spring housing 64 (FIG. 3) including an upper flange 66 and a web 67 which extends between the upper flange 66 and the lower flange 68. The web 67 projects upwardly slightly above the upper flange 66 to provide a ridge 69 for reasons appearing hereinafter.

The mounting plate 51 (FIG. 3) has an integral, rearwardly extending stop flange 72 which is preferably struck from the plate material and is engageable by the lower flange 68 to positively limit clockwise rotation of the latch support member 53 around the axle 62. The latch bolt 36 is rotatably supported at its upper end upon the pivot pin 73 which is located above and substantially rightwardly of the axle 62 when the flange 68 is in engagement with the flange 72 and the arm 63 is substantially horizontal, as appearing in FIG. 1. Thus, during the initial movement of the latch support member 53 away from its fully latched position of FIG. 3, the latch bolt 36 and lever 37 must be raised somewhat, as shown in FIG. 5.

The latch bolt 36 is preferably (but not necessarily) in one piece and has a substantially semicircular upper end 74 which curves around the leftward side of the axle 62 so that the bolt will not interfere with the clockwise, unlatching movement of the latch support member 53, as appearing in FIG. 6. A spiral spring 76 is held under tension between an integral car 77 on the upper end 74 of the latch bolt 36 and an anchor pin 78 (FIG. 3) projecting from the arm 63 into the space between the flanges 66 and 68 near the web 67. Thus, the latch bolt 36 is constantly urged in a clockwise direction around its pivot pin 73.

A coil spring 81 (FIG. 4), which encircles the axle 62, has a hook 82 at its rearward end (FIG. 3) which is engaged in the slot 83 in the front sidewall 56 of the housing 54. Said spring 81 has a hook 84 (FIG. 4) on the frontward end which is received through a slot 86 in the mounting plate 51. The coil spring 81 is under constant tension whereby it urges the latch support member 53 is a counterclockwise direction, as appearing in FIG. 8, toward a position in which the latch bolt 36 engages the lower edge of the flange 72 and the upper part of the peripheral wall 58 (FIG. 3). The peripheral wall 58 may extend, as shown in FIG. 4, somewhat beyond the front sidewall 56 of the housing 54 in order to provide a weather shield for the coil spring 81.

A primary keeper 90 (FIG. 3) is pivotally mounted upon a pivot pin 91 which is rigidly secured to the mounting plate 51 near, but rightwardly of, the web 67 on the arm 63. The primary keeper 90 has an integral, downwardly opening hook 92 which is engageable with the ridge 69 on the U-shaped projection 64, when in its FIG. 3 position, for positively preventing upward or counterclockwise movement of the U-shaped projection 84, hence of the arm 63.

A spring support flange 93 is integral with and pref erably struck rearwardly from the mounting plate 51 adjacent to and rightwardly of a downward projection 94 on the primary keeper 90. Accordingly, engagement of the flange 93 by the projection 94 positively limits counterclockwise movement of the keeper 90 around the pivot pin 91. The primary keeper 90 has a rightward projection 96 which overlies the flange 93, and a spiral spring 97 is held. under compression between the flange 93 and the rightward projection 96, thereby constantly urging the primary keeper 90 in a counterclockwise direction, as appearing in FIG. 3, so that the projection 94 is positively urged toward the flange 93. However, the stop flange 72 is located so that the hook 92 firmly engages the ridge 69 just before the projection 94 engages the flange 93. A pin 98 is secured to the flange 93 and is received upwardly into the spring 97 for positioning same.

A thurnbgrip 99 is integral with and projects upwardly from the primary keeper 90 for manually moving same against the contrary urging of the spring 97 away from engagement with the ridge 69, after which the latch support member 53 can then be rotated in a counterclockwise direction. The upper surface 102 of the hook 92 and the rightward surface 103 of the web 67 are shaped so that downward, clockwise movement of the latch support member 53 from its FIG. position toward its FIG. 3 position will automatically cause the web 67 to rotate the primary keeper 90 in a clockwise direction until the ridge 69 can slide under the hook 92 and be positively gripped thereby.

The secondary keeper 110 (FIG. 1) is comprised of a substantially flat body member 111 which is pivotally supported near the upper edge thereof by the pivot pin 112. The pivot pin 112 is in turn rigidly secured to a support plate 113 which is riveted or bolted to the door 12 so that the pivot pin 112 is preferably (but not necessarily) spaced at a point from the axle 62 slightly greater than the distance between said axle and the outer end of the arm 63. The arm '63 has a downward and frontward projection 115, which is located at the outer end (FIGS. 1 and 12) of the arm 63 when the keeper pivot pin 112 is located as specified above. The projection 115 is engageable on its rightward side by the lug 116 which is integral with and extends downwardly from the body member 111 of the keeper 110. The lug 116 is preferably located on the body member 111 so that it hangs directly below the pivot pin 112 under the influence of gravity. The projection 115 and lug 116 (FIGS. 11 and 12) have openings 117 and 118, respectively, which are aligned when latch assembly 11 is in its normal latched position of FIG. 1.

The body member 111 (FIG. 1) has an arcuate edge 121 which extends over and is engageable by the upper edge 122 (FIG. 12) of the projection 115 when the keeper 114] is in its normal depending position. Accordingly, if the primary keeper should be accidentally disconnected from the ridge 69 and if simultaneously the spring 43 should fail, the presence of the arcuate edge 121 in the path of the projection 115 will positively prevent the latch support member 53 from rotating in a counterclockwise direction, under the influence of the coil spring 81 or by irregular movements of the truck, for example, and thereby releasing the hook 42 from the hook 39.

An integral flange 123 (FIG. 1) is provided on the support plate 113 rightwardly of the pivot pin 112 for engagement by the lug 116 (FIG. 11), in which position the keeper 110 is completely inoperative with respect to the movement of the latch support member 53 and its arm 63.

The secondary keeper 110 can be manually moved out of its position obstructing upward movement of the arm 63 by manually engaging the lug 116 and moving same in a counterclockwise direction around the pin 112 and away from the projection 115. However, when the arm or handle 63 is returned toward its latched position of FIG. 1, the projection 115 strikes the upper edge 124 of the body member 111 on the leftward side of the pivot pin 112 and thereby pivots the keeper 110 out of its way, as shown in FIGS. 9 and 10, until the projection 115 reaches a position below the arcuate edge 121 whereupon the keeper 110 will swing into its FIG. 1 position and thereby block upward movement of the projection 115, hence the arm 63.

The length and radius of the arcuate edge 121 are preferably selected so that the edge 121 cannot be moved away from a position obstructing the upward movement of the projection 115 when a conventional sealing ring or loop is threaded through the openings 117 and 118 and sealed. l

OPERATION The operation of the door lock structure described above will be apparent from such description to a person of ordinary skill in the performance and/or manufacture of truck door locks. However, primarily for the purpose of convenience, the lock operation will now be summarized. The lock structure of the invention will normally be manufactured and installed so that the upper end of the hook 39 on the catch lever 37 will be spaced from the top plate 18, and the lower surface of the catch lever 37 will be spaced from the bottom wall 17 when the catch assembly 13 is properly engaged by the latch assembly 11 in their FIG. 1 and FIG. 3 positions. Thus, the catch assembly 13 will be urging the latch assembly 11, hence the door 12, toward the bed 14 with a force of somewhere between and 500 pounds. Much of this force will be absorbed by the compression of the resilient weather seal 15 between the lower edge of the door 12 and the bed 14.

When it becomes desirable to disengage the latch bolt 36 from the catch lever 37, the secondary keeper is rotated in a counterclockwise direction, the primary keeper 90 is pivoted in a clockwise direction and the handle 63 is manually urged upwardly and pivoted around the axle 62. With the latch bolt 36 arranged and supported upon the latch support member 53 as appearing in FIG. 3, the spiral spring 43 will oppose initial up ward movement of the arm 63, because such movement will necessitate a slight raising of the latch bolt 36, hence a further compression of the spiral spring 43. The purpose of this arrangement is to further avoid the possibility of an accidental unlatching of the bolt 36 from the catch lever 37. However, it will be recognized that this further precaution can be omitted merely by placing the pivot axis of the pivot pin 73 substantially directly above the axle 62.

Further counterclockwise rotation of the latch support member 53, as to its position of FIG. 6, will permit the spiral spring 43 to move the catch lever 37 into its lowermost position against the bottom wall 17. Thus, the hook 42 on the latch bolt 36 can then be rotated with the support member 53 in a counterclockwise direction through the opening 34 in the top plate 18. The spiral spring 76 (FIG. 3) will tend to urge the latch bolt 36 into its FIG. 8 position with respect to the support member 53, and the coil spring 81 will urge the latch support member 53 toward its FIG. 7 position with respect to the plate 51, where they will remain until it becomes desirable to reconnect the latch bolt 36 with the catch lever 37. This is accomplished by merely rotating the latch support member 53 in a clockwise direction after the door 12 is located in its substantially closed position of FIG. 1. The primary and secondary keepers 90 and 110 will be automatically moved out of the way of the latch support member as it moves into the latched position. Also, the latch bolt 36 will be swung through the opening 34 in the plate 18 and will automatically engage the lever hook 39.

Should the spiral spring 43 break during normal operation, it will permit the catch lever 37 to move upwardly and downwardly substantially between a position against the top plate 18 and some position spaced slightly below the top plate. However, due to the urging of the spiral spring 76 (FIG. 3), the latch bolt 36 will be positively and continuously urged to remain in engagement with the hook 39 on the catch lever 37, and the top plate 18 will positively limit the upward movement of the lever 37, and thereby act as a fail safe limit for the latch bolt 36.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In an upwardly acting door for a truck having a bed, a door lock structure, comprising:

an actuating member pivotally mounted upon the door near the lower edge thereof for movement around a first axis parallel with said bed when said lower edge is adjacent thereto;

a latch bolt pivotally secured to said actuating member near said first axis for movement around a second axis parallel with said first axis, said latch bolt having a hook portion adapted to extend below said lower edge of said door;

wall means rfixedly secured to said bed and defining a chamber therein, at least a portion of the top of said chamber being open for permitting said latch bolt to extend therein;

a lever disposed within said chamber and pivotally secured near one end thereof to said wall means for pivotal movement around a third axis substantially parallel with and located below said first and second axes;

hook means on said lever near the other end thereof and engageable with the hook portion of said latch bolt for maintaining the lower edge of said door closely adjacent to said bed;

stop means interconnected to said wall means and adapted to coact with a portion of said lever for limiting upward pivotal movement thereof relative to said bed; and

resilient means coacting between said wall means and said lever for urging said hook means downwardly away from said stop means.

2. A lock structure according to claim 1, wherein said resilient means includes spring means coacting between said lever and said wall means, said spring means contacting said lever at a position spaced radially outwardly from said hook means relative to said third axis.

3. A lock structure according to claim 1, wherein the longitudinally extending direction of said lever is substantially transverse to the longitudinally extending direction of said latch bolt when the hook portion of said latch bolt is in engagement with the hook means on said lever.

4. A lock structure according to claim 1, wherein said third axis is vertically spaced below said first and second axes and is horizontally laterally offset therefrom whereby swingingmovement of said lever causes said hook means to move substantially in a vertical direction, whereas swinging movement of said latch bolt about said second axis as the hook portion of said latch bolt approaches said hook means causes said hook portion to move substantially in a horizontal direction.

5. A lock structure according to claim 1, including an elongated arm on said actuating member having a projection thereon spaced substantially from said first axis;

hooked keeper means pivotally supported upon said door near said edge and engageable with said projection for holding said arm in a predetermined position when the hook portion of said latch bolt and the hook means of said lever are engaged and opposing the urging of said resilient means; and

second resilient means yieldably urging said hooked keeper means toward said position of engagement with said projection.

6. A lock structure according to claim 5, including a second projection on said arm remote from said first axis;

a cammed keeper pivotally supported upon said door near said lower edge thereof, the pivot axis of said cammed keeper being spaced from said first axis a distance greater than the distance between said first axis and said second projection;

means defining an arcuate cam edge on said cammed keeper extending through a substantial arc and engageable with said second projection for opposing upward movement of said second projection when said arm is substantially in said predetermined position;

lug means on said cammed keeper engageable with said second projection for preventing rotation of the cammed keeper in one rotational direction when said arm is in said predetermined position; and

bracket means secured to said door structure near said cammed keeper engageable by said lug means for holding said cammed keeper completely out of the path of movement of said arm and said actuating member.

7. In a lock structure for an upwardly acting truck door having a lower edge engageable with the bed of the truck, said lock structure having a latch bolt mounted upon the door and adapted to extend below the lower edge of the door, a catch box comprising:

an elongated casing defining a lever chamber having top wall means, said casing being secured to said bed, and said top wall means having an opening through which said latch bolt is receivable;

an elongated lever disposed within said lever chamber and pivotaly secured near one end thereof to said casing for movement around an axis substantially parallel with said bed and transverse of said lever;

hook means on said lever near the other end thereof and engageable with said latch bolt opposing movement of said latch bolt away from said casing, said hook means being spaced below and engageable with said top wall means; and

resiliently flexible means between said top wall means and the other end of said lever yieldably urging said hook means away from said top wall means.

8. In a lock structure for an upwardly acting door of a truck having a bed, said lock structure including a manually operable arm pivotally mounted upon said door, and a latch bolt connected to said arm near the pivot axis thereof and engageable with a catch mounted in said bed when said arm is in a predetermined position, keeper means for holding said arm in said predetermined position, comprising:

lateral projection means fixedly secured to said arm 9 and spaced substantially from the pivot axis of said arm;

a keeper pivotally mounted upon said door near the lower edge thereof at a distance from said first-mentioned axis which is different from the distance between said projection means and said first-mentioned axls;

lug means on said keeper positionable adjacent to and engageable with said projection means when said arm is in said predetermined position for limiting rotation of said keeper in one direction;

said projection means and said lug means each having an opening therein with said openings being positionable substantially in alignment with one another when said arm is in said predetermined position and said lug means is positioned adjacent said projection means;

said keeper having an arcuate edge substantially concentric with the pivot axis of the keeper and engageable with said projection means when said lug means is near said projection means for positively preventing upward movement of the adjacent end of said arm away from said predetermined position; and

bracket means secured to said door structure near said keeper for engagement by said lug means to support said keeper in an inoperative position completely out of the path of upward movement of said arm away from said predetermined position.

9. A lock structure according to claim 8, wherein said arcuate edge is approximately 90 degrees in extent so that said lug means can be moved a substantial distance away from said projection means Without effecting disengagement of said arcuate edge by said projection means; and

said lug means being integrally connected to said arcuate edge adjacent one end thereof and extending outwardly therefrom in a direction substantially radially relative to the pivot axis of said keeper; and said projection means and said lug means each having planar surfaces thereon adapted to be positioned adjacent one another when in said predetermined position whereby said openings are substantially aligned for permitting reception of a sealing ring.

References Cited UNITED STATES PATENTS 1,250,574 12/1917 Ferris 2921 13 1,495,373 5/1924 Witten 292108 1,495,374 5/1924 Witten 292l36 2,523,845 9/ 1950 Roseburrough 292-l08 2,741,505 4/1956 Courney 29234l.17 3,045,464 7/1962 Braginetz 7 0-l44 3,108,833 10/1963 Christensen et a1. 292-413 3,346,288 10/1967 Cosentino 29292 3,399,921 9/1968 Trost et al. 292--35 MARVIN A. CHAMPION, Primary Examiner R. L. WOLFE, Assistant Examiner 

